Refrigerating apparatus



Oct. 25, 1938.

M. G. SHOEMAKER REFRIGERAT ING APPARATUS Filed Oct. 30, 1956 WI TN ESSES:

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'MnLccLM G.

INVENTOR SHOEMRKER ATTORNEY Patented Oct. 25, 1938 2,133,962

UNITED STATES PATENTOFFAICE nnrmonna'mvc APPARATUS Malcolm G. Shoemaker, Springfield, Mass, assignor to Westinghouse Electric & Manufacturing Company,-East Pittsburgh, 2a., a corporation of Pennsylvania Application October 30, 1936, Serial No. 108,361 7 Claims. (CL 62-415) My invention relates to refrigerating appa- 28. The valve plate 25 closes the ports '25 and 'ratus having a plurality of evaporator elements and has for an object to provide improved apparatus of this kind.

5 A further object of the invention is to provide an improved multi-evaporator refrigerating system having a high side float valve mechanism commonto the evaporators with means for selecting the evaporator to receiverefrigerant from 10 the valve mechanism.

7 These and other objects are effected by my invention as will be apparent from the. following description and claims taken in connection with the accompanying drawing, forming a part of this 15 application in which:

Fig. 1 is a diagrammatic view of a refrigerating system constructed in accordance with my invention; and

Fig. 2 is an enlarged sectional view of the float 20 valve employed in the system shown in Fig. l.

Referring now to the drawing, the numerals i and II indicate relatively high and low temperature chambers which are. refrigerated by evaporators l2 and i3, respectively. Refrigerant va- '5 porized in the evaporators i2 and I3 is withdrawn therefrom by a compressor l4 through a conduit l5 common to both evaporators. The compressor I4 is driven, preferably, by a motor l5 and operates to compress the vapor withdrawn from 30.12116 evaporators l2 and I3 to a relatively high pressure in a condenser H. The condenser I1 is cooled in any suitable manner, such as, for

7 example, by a fan l8, whereby the high pressure vapor is condensed. A reservoir l9 maybe pro- 35 vided for collecting refrigerant liquefied in the condenser H. Y

Condensed refrigerant is conveyed through a conduit 20 from the reservoir 19 to a float valve structure, shown generally at 2!, and connected 40 to the evaporators l2 and i3 by conduits 22 and '23. A valve 24 actuated by a solenoid 25 is disposed in the conduit 22 for controlling the flow of refrigerant therethrough. The construction and operation of solenoid operated valves is well 45 known in the art and will not be described, other than to say that the valve 24 is open when th solenoid 25 is energized and is closed when the solenoid 25 is deenergized.

The float valve structure 2| includes a casing 50 26 that receives condensed refrigerantfrom the conduit 20. The conduits 22 and 23 terminate in ports 21 and 28 communicating with themterior of the casing 26. A valve plate 29, pivoted at 3|, is actuated by a float 32 that rises and falls withthe level of liquid refrigerant in the casing in the casing 25. when the solenoid valve 24 is is selectively controlled by the solenoid valve.

-in the casing 25.

by refrigerant is supplied to the evaporator I3, 45

21, successively, as the level of the refrigerant in the casing 25 falls..

The position of the float 22 and valve plate 29 shown in the drawing, indicates that the solenoid 6 valve 24 is closed so that liquid cannot pass through the port 21. Accordingly, the float 52 controls'the flow of refrigerant passing through the port 28 in response to the level of refrigerant opened, refrigerant passesimmediately through theport 21 and conduit 22 to the evaporator i5.

As the level of refrigerant in the casing 25 drops,

the valve plate 29 closes the port 25 and controls the flow of refrigerant through the port 2'! in respouse to the level of refrigerant inthe casing 25.

The operation of the evaporator: 12 and l5 when solenoid 25 is energized, the valve 24 is open and flow of condensed refrigerant to the evaporator I2 is eflected under control of the float 32. At this time, the valve plate 28-closes the port 28 so that the conduit 22 and evaporator l2 receive no condensed refrigerant.

Operation of the evaporator I2 is effected by deenergizing the solenoid 25, whereby the valve 24 closes. Flow of refrigerant through the port'2'l and conduit 22 to the evaporator .I2 is then terminated. Accordingly, the level of refrigerant in the float valve' structure 2| rises 'as the com- 30 pressor I4 is operated and refrigerant is supplied to the evaporator vl3 through the port .25 and conduit 23 in response to the level of refrigerant Automatic control of the operation of the evaporators l2 and i2 may be eflected by thermostats 35 and 36 that respond'to temperatures within the respective chambers HI and II and which control the energization of the motor l6 and solenoid 25. The source of electric power for 40 the motor l6 and solenoid 25 is represented by 7 line conductors Li and In.

when closed, the thermostat 25 energizes the motor l5 for operating the compressor I4 wherethe solenoid valve 24 beingclosed. The energizing circuitincludes the line conductorLi, motor l6, a conductor 51, thermostat 25, and line conductorLa when the thermostat 35 is closed, the motor l5 and solenoid 25 are'energized and the compressor operates to circulate refrigerant through the evaporator i2. I have shown the solenoid-25 arranged in series with the motor i5 when the latter is energized by the thermostat 55, but it will be understood that it may be connected otherwise for energization at this time. The energizing circuit for the motor I6 .and solenoid 25 includes the line conductor La motor I6, a conductor 33 having the solenoid 25 connected therein, 'the thermostat 35, a conductor 33, and the line conductor La.

The electric connections disclosed give preference to the thermostat 36 when both thermostats 35 and 36 are closed, as the-thermostat 36 forms a shunt across the circuit including the conductor 38, solenoid 25, thermostat 35 and conductor 39. Accordingly, the solenoid 25 is deenergized under this condition and refrigerant is, therefore, passed to the low temperature evaporator I3 associated with the thermostat 36. It will be understood that the thermostat 35 and its associated higher temperature evaporator I2 may be given preference, if desired.

Operation As shown in Fig. 1, the temperatures of the air in the chambers I and It are below values at which their respective thermostats close and, therefore, the motor I6 and compressor I4 are inactive. Assume a rise in temperature in the chamber III to the value at which the thermostat 35 closes. The motor I6 and solenoid 25 are energized by the aforementioned circuit so that operation of the compressor I4 and opening of the valve 24 are effected.

Condensed refrigerant in the casing 26 of the valve structure 2I is passed through the port 21 and conduit 22 to the evaporator I2 under control of the float 32. As the valve plate 23 covers the port 28, no condensed refrigerant. is passed to the evaporator I3. Operation of the compressor I4 continues until the temperature of the air in the chamber I0 is depressed to the value at which the thermostat 35 opens whereby the compressor I4 is stopped and the solenoid 25 is deenergired. During periods when vaporization is effected in the evaporator I2, the evaporator I3 is filled, substantially, with refrigerant but vaporization is not effected therein-as its temperature is lower than the temperature of vaporization in the higher temperature evaporator I2. Vapor from the evaporator I2 is prevented from condensing in the low temperature evaporator I3 as the latter is substantially filled ,with liquid refrigerant.

Assume a .rise in temperature within the low temperature chamber II to the value at which the thermostat 36 closes the aforementioned circuit for energizing the motor I6. Operationof the compressor I4 is initiated and withdraws vaporous refrigerant which is present in the orator I3. When all refrigerant is vaporized in the evaporator I2, evaporation is effected at relatively low pressure in the evaporator I3 and continues until the-temperature within the chamber II is depressed to a predetermined value at which the thermostat 36 operates to deenergize the motor l6;

Accordingly, when evaporation is ellected in the low temperature evaporator I3, the higher I temperature evaporator is substantially devoid of liquid refrigerant and when evaporation is effected in the high temperature evaporator l2, the low temperature evaporator is substantially filled with liquid refrigerant. It will be apparent that there is a larger amount of liquid refrigerant in the high side of the system when vaporization is effected in the low temperature evaporator I3 than when vaporization is effected in the high temperature evaporator I2. The added amount of refrigerant in the high side during refrigeration of the low temperature evaporator I3 collects in the float valve casing 26 and effects raising of the float 32 sufllciently to open the port erence as the thermostat 36 shunts the thermostats 35 and solenoid 25, as described heretofore. Accordingly, the solenoid is deenergized and the valve 24 is closed, whereby condensed refrigerant is supplied to the evaporator I3 only. When the temperature of the air in chamber II is depressed to the desired value, the thermostat 36 opens the shunt across the solenoid 25, which is energized and transfers the flow of refrigerant from the evaporator I3 to the evaporator I2, The compressor I4 continues to operate as the motor I6 is energized by the closed thermostat 35.

From the foregoing, it will be apparent that I have provided an improved two temperature refrigerating system having a novel float valve structure for controlling the flow of refrigerant to the high and low temperature evaporators with means for selecting the evaporator to receive refrigerant.

It will be understood that other forms of refrigerant condensing units niay be' employed without departing from the spirit of the invention. The various control instrumentalities are shown byway of example and in their simplest form for the sake of clearness and it will be understood that other forms or types. of control devices may be employed. The specific construcbe considered as the preferred form but it is apparent that other forms may be adopted.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.--

What I claim is:

1. In refrigerating apparatus, the combination of first and second evaporators, means for supplying condensed refrigerant to the evaporators, a valve structure for controlling the supply of condensed refrigerant to the. evaporators and including first and second discharge ports for respectively passing refrigerantto the first and second evaporators, means responsive to the' level of the liquid in the valve structure for successively opening the first and second ports as the level of refrigerant in the structure rises, and means for controlling the passage of redensing refrigerant vaporized in the evaporators,

a container for receiving the condensed refrigerant and having first and second outlets connected to the first and second evaporators, re-

spectively, a valve cooperating with the outlets and movable in response to the level of liquid in the container, said valve opening the first and second outlets successively as the level in the container rises, and means for controlling the passage of refrigerant through the first outlet and movable to a position wherein the passage of refrigerant throughthe first outlet is prevented, whereby the valve cooperates with the second outlet to supply refrigerant to the second evaporator.

3. In refrigerating apparatus, the combination of first and second evaporators, means for condensing refrigerant vaporized in the evaporators, a container for receiving the condensed refrigerant and having firstand second outlets connected to the first and second evaporators, respectively, a float positioned in response to .the level of liquid in the container, a movable valve member associated with the outlets and actuated by the float in such manner that the flow of re-.

frigerant through the first port is controlled thereby while the second. port is closed, and means for controlling the passage of refrigerant through the first port and adjustable for preventing the passage of refrigerant therethrough,

whereby the level of liquid in the container rises and the valve member cooperates with the second port for controlling the fiow of refrigerant therethrough.

4. In refrigerating apparatus, the combination of first and second evaporators, means for 'condensing refrigerant vaporized in the evaporators, a fioat valve, structure for receiving the refrigerant condensed by said condensing means, said float structure having first and second outlets for passing refrigerant to the firstand second evaporators, respectively, and means for selecting the outlet of the floatv structure which is effective to pass refrigerant.

5. In refrigerating apparatus; the combination of first and second evaporators, means for .condensing refrigerant vaporized in the evaporators,

a float valve structure for receiving the refrigerant condensed by said means, said float struc- 1,-

,ture having first and second outlets for passing refrigerant to the first andisecond evaporators, respectively, and means responsive to temperatures produced by the respective evaporators for selecting the outlet which is effective to pass refrigerant.

6. In refrigerating apparatus, the combination of first and second evaporators, a compressor for circulating refrigerant through the evaporators,

and means including first and second passages '1.

first and second refrigerant passages respectively connected to the first, and second evaporators for selectively controlling the fiow of refrigerant to the evaporators, said means being actuated in response to variable levels of refrigerant condensed by said condensing unit.

MALCOLM G.. SEOEMAKER. 

